Bonding structure and method of fabricating the same

ABSTRACT

A bonding structure and a method of fabricating the same are provided. A first substrate having a first bonding element and a second substrate having a second bonding element are provided, wherein at least one of the first bonding element and the second bonding element is formed with an alloy. A bonding process is performed to bond the first bonding element with the second bonding element, wherein a diffusion liner is generated at the exposed, non-bonded surface of the bonding structure.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan applicationserial no. 99103648, filed Feb. 06, 2010. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of specification.

BACKGROUND OF THE INVENTION

1. Technical Field

The disclosure relates to a bonding structure and a method offabricating the same, and more particularly to a bonding structure inwhich the reliability of the bonding structure is enhanced and a methodof fabricating the same.

2. Background

As the requirement on the complexity and precision of an integratedcircuit design continues to increase, various techniques for reducingthe feature size of a semiconductor device and/or increasing theintegration of an integrated circuit are being explored. Thefabrications of high-density metal interconnect and three-dimensionalintegrated circuits (3D-IC) have been proven to be feasible approachesfor upgrading the integration density and improving the performance ofsemiconductor products.

Conventionally, copper are used in conductive lines for connectingsemiconductor devices to a substrate or bonding metal for stacking chipsor wafers to achieve 3D-IC configurations. However, the application ofthese metal bonding structures suffers some adverse challenges which areyet to be overcome.

FIG. 1 is a schematic cross-sectional view illustrating a conventionalbonding structure. Referring to FIG. 1, the bonding structure 100 mainlyincludes a first substrate 110 and a second substrate 120. The firstsubstrate 110 includes a first bonding element 112 disposed thereon.Likewise, the second substrate 120 includes a second bonding element 122disposed thereon. The first and the second bonding elements 112, 122 arecomposed of a metal, such as copper. As a bonding process is performedon the substrates 110 and 120, the first and the second bonding elements112 and 122 are bonded together, such that the first substrate 110 isconnected to the second substrate 120. Alternatively, an adhesive film130 may be formed between the first and the second substrates 110, 120,enclosing the bonding structure.

As shown in FIG. 1, after the bonding process, the resulting bondingstructure remains exposed to the ambient environment, such as air, or incontact with the adhesive film 130, which frequently causes damages tothe bonding structure. A formation of a nonconductive oxide film on thesurface of the bonding structure may also occur, and the presence of thenonconductive oxide film would lead to a high contact resistance in thedevice. Moreover, when integration increases, stress-induced voiding andelectromigration often happen, especially in an exposed metal surface;hence, device failure is resulted. Further, as the feature size of abonding pad or a contact becomes smaller and the level ofinterconnections continues to increase, the above-mentioned problemsaffecting a bonding structure become even more significant. Ultimately,the reliability of the bonding structure and the final device areimpacted negatively.

SUMMARY

The disclosure is directed to a bonding structure for integrating twosubstrates. The bonding structure includes a diffusion liner at theexposed, non-bonded surface thereof. Therefore, the resistance tooxidation, electromigration and stress-induced voiding is improved.

The disclosure is also directed to a method of fabricating a bondingstructure. The method includes forming a diffusion liner layer at theexposed, non-bonded surface of the bonding structure. Thus, thereliability of the bonding structure and the final device is enhanced.

The disclosure provides a bonding structure including a first substratehaving at least a first bonding element, and a second substrate havingat least a second bonding element. At least one of the first bondingelement and the second bonding element is formed with an alloy having atleast two metal components. The bonding structure further includes adiffusion liner layer configured at the exposed, non-bonded surface ofthe resulting bonding structure when the first bonding element is fusedwith the second bonding element, wherein the diffusion liner layer isconstituted essentially with the at least two metal components used informing the first bonding element and the second bonding element.

According to an exemplary embodiment of the disclosure, theconcentrations of the at least two metal components in the diffusionliner layer is different from the concentrations of the at least twometal components in the at least one bonding element.

According to an exemplary embodiment of the disclosure, the weightpercentage of one metal component of the at least two metal componentsin the at least one bonding element is between about 0.5% to about 15%,while the weight percentage of the same one metal component of the atleast two metal components in the diffusion liner layer is greater than95%.

According to an exemplary embodiment of the disclosure, the alloy is acopper-based alloy.

According to an exemplary embodiment of the disclosure, a secondarycomponent in the alloy includes at least one of aluminum, titanium,magnesium and chromium.

According to an exemplary embodiment of the disclosure, an adhesivelayer is sandwiched between the first and the second substrates forfilling the gap therebetween.

The disclosure further provides a method of fabricating a bondingstructure. The method includes providing a first substrate and a secondsubstrate. The first substrate includes at least a first bonding elementand the second substrate includes at least a second bonding element,wherein at least one of the first bonding element and the second bondingelement is formed with an alloy including at least two metal components.A bonding process is then performed to fuse the first bonding elementand the second bonding element and to generate a diffusion liner at anexposed, non-bonded surface of the resulting bonding structure.

According to an exemplary embodiment of the disclosure, the diffusionliner is formed with the at least two metal components from the at leastone bonding element.

According to an exemplary embodiment of the disclosure, theconcentrations of the at least two metal components in the diffusionliner layer is different from the concentrations of the at least twometal components in the at least one bonding element.

According to an exemplary embodiment of the disclosure, after thebonding process, an annealing process is performed.

According to an exemplary embodiment of the disclosure, the bondingprocess is performed at a temperature of about 300° C. to about 500° C.for about 30 minutes to about 120 minutes.

According to an exemplary embodiment of the disclosure, the bondingprocess includes a one-step bonding process or a two-stepbonding-plus-annealing process.

According to an exemplary embodiment of the disclosure, at least one ofthe first bonding element and the second bonding element is formed witha copper-based alloy that includes at least one of aluminum, titanium,magnesium and chromium.

According to an exemplary embodiment of the disclosure, the method alsoincludes forming an adhesive film, sandwiched in the gap between thefirst substrate and the second substrate.

Several exemplary embodiments accompanied with figures are described indetail below to further describe the disclosure in details.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating a conventionalbonding structure.

FIGS. 2A and 2B are schematic cross-sectional views illustrating amethod of fabricating a bonding structure according to an exemplaryembodiment of the disclosure.

FIGS. 3A and 3B are schematic cross-sectional views illustrating aprocess of fabricating a bonding structure according to an exemplaryembodiment of the disclosure.

FIGS. 4A to 4B are schematic cross-sectional views illustrating a methodof fabricating a bonding structure according to an exemplary embodimentof the disclosure.

FIGS. 5A and 5B are schematic cross-sectional views illustrating aprocess of fabricating a bonding structure according to an exemplaryembodiment of the disclosure.

DETAILED DESCRIPTION OF DISCLOSED EMBODIMENTS

In the following description, reference is made to various exemplaryembodiments in which the disclosure may be practiced, and it is to beunderstood that other embodiments may be employed without departing fromthe disclosure. The disclosure is not limited to a particular form ofbonding structure, and is applicable to any bonding structure, such asconductive wires, bumps, balls, pads, pins, or the like. However, tofacilitate the explanation of the disclosure, the following discussionis exemplified with a lock-and-key bonding structure. Further, thedisclosure is applicable for all types of semiconductor wafers,integrated circuit (IC) chip and wafer assembly. For example, thebonding structure of the disclosure can be applied to bond integratedcircuits (IC) or chip to a substrate or to interconnect chips or wafersin a three-dimensional (3-D) integrated circuit assembly.

First Embodiment

FIGS. 2A to 2B are schematic cross-sectional views illustrating a methodof fabricating a bonding structure according to an exemplary embodimentof the disclosure. Referring to FIG. 2A, a first substrate 210 and asecond substrate 220 are provided. The term “substrate” used in thediscussion refers to any supporting structure, such as a semiconductorsubstrate, silicon-on-insulator, epitaxial layers of silicon supportedon a base and other semiconductor structures made of silicon, germanium,germanium silicon, gallium arsenide, or the like materials. The“substrate” can also be a silicon wafer in a wafer bonding process.Further, the first substrate 210 and the second substrate 220 mayinclude an active layer supporting one or more integrated circuit (IC)devices (not shown). As shown in FIG. 2A, the first substrate 210includes at least a first bonding element 212, and the second substrate220 includes at least a second bonding element 222. The second substrate220 is configured above the first substrate 210 to be integrated withthe first substrate 210.

In this exemplary embodiment of the disclosure, the first bondingelement 212 is, for example, a metallized via extending downward intothe first substrate 210. The metallized via 212 could be in electricalcommunication with integrated circuit (IC) devices (not shown) alreadyformed on the first substrate 210 or electrically isolated from the ICdevices (not shown) on the first substrate 210. It should be understoodthat the metallized via 212 could have any appropriate thickness and anypolygonal shape. Further, the bonding surface 216 of the metallized via212 could be flat, protruded or recessed. It should also be understoodthat the metallized via 212 may be formed in a dielectric medium (notshown) supported on a substrate.

The first bonding element 212 is formed by, for example, etching thefirst substrate 210 to form a recess and allowing the recess to bepartially filled with a bonding material. Further, a liner layer 218 maybe formed on the surface of the recess prior to filling the recess withthe bonding material. In this exemplary embodiment of the disclosure,only the bonding surface 216 is not covered by the liner layer 218. Thematerial of the liner layer 218 includes, for example, tantalum (Ta),tantalum nitride (TaN), titanium (Ti), titanium nitride (TiN) ortitanium tungsten (TiW).

In this exemplary embodiment of the disclosure, the bonding material isa metal alloy having two or more components. In an exemplary embodimentof the disclosure, the metal alloy is a copper alloy, for example. Themetal alloy also contains a secondary component that includes, but notlimited to, titanium (Ti), magnesium (Mg), aluminum (Al), chromium (Cr).Further, the principle component in the metal alloy (such as, copper ina copper-based alloy) is about 85% to about 99.5% by weight, forexample, while the secondary component in the metal alloy is about 15%to about 0.5% by weight, for example.

In this exemplary embodiment of the disclosure, the second bondingelement 222 is a T-shaped structure which includes a stud 222 aprotruding above the top surface 220 a of the second substrate 220 and alateral portion 222 b embedded at the top surface 220 a of the secondsubstrate 220, as shown in FIG. 2A. The second bonding element 222 isformed with a metal, such as copper.

According to an exemplary embodiment of the disclosure, a liner layer228 may be formed between the second bonding element 222 and the secondsubstrate 220, between the stud 222 a and the lateral portion 222 b, andon the exposed, non-bonding surfaces of the second bonding element 222.Please note that only the bonding surface 226 is not covered by theliner layer 228. The material of the liner layer 228 includes, forexample, tantalum (Ta), tantalum nitride (TaN), titanium (Ti), titaniumnitride (TiN) or titanium tungsten (TiW).

Referring to FIG. 2B, the second bonding element 222 on the secondsubstrate 220 is brought into alignment and in contact with the firstbonding element 212 on the first substrate 210. A bonding process isperformed to integrate the first substrate 210 with the second substrate220 through the physical bonding of the first bonding element 212 andthe second bonding element 222. The bonding process includes a thermalprocess. In an exemplary embodiment of the disclosure, the thermalprocess is conducted at a temperature of about 300° C. to about 500° C.for at least 30 minutes. In another exemplary embodiment of thedisclosure, the thermal process is conducted at a temperature betweenabout 350° C. to about 400° C., and the duration of the thermal processranges from 30 minutes to 2 hours. Depending on the requisite of thefabrication process, an annealing process may be performed subsequent tothe bonding process to enhance the bonding quality of the first bondingelement 212 and the second bonding element 222.

According to this exemplary embodiment of the disclosure, during thebonding process or the annealing process for promoting the bondingquality of the first bonding element 212 and the second bonding element222, a diffusion liner layer 230 is generated at the exposed, non-bondedor non-bonding surfaces of the bonding elements. More specifically, inthis exemplary embodiment of the disclosure, a diffusion liner layer 230is generated at the non-bonded surface 216 a of the bonding surface 216of the first bonding element 212. In accordance to the embodiment of thedisclosure, the self-forming diffusion liner layer 230 consists mostlyof some of the metal components of the metal alloy used in forming thebonding elements. In an exemplary embodiment of the disclosure, in whichthe metal alloy is a copper-based alloy containing a secondary componentof titanium (Ti), the diffusion liner layer 230 is formed mostly withtitanium. However, it should be appreciated that the secondary componentmay also include magnesium, aluminum, chromium, and/or other metals, andthe diffusion liner layer 230 may form mostly of magnesium, aluminum,chromium, and/or other metals.

The formation of the self-forming diffusion liner layer 230 may probablydue to a segregation of the metal components (for example, copper andtitanium) in the metal alloy at the elevated temperature and anaggregation of the one or more metal components in the alloy (forexample, titanium) at the exposed, non-bonded surface 216 a of the firstbonding element 212. Alternatively speaking, the concentrations of theat least two metal components (for example, copper and titanium) in thediffusion liner layer 230 may be different from the concentrations ofthe at least two metal components (for example, copper and titanium) ata bulk of the first bonding element 212. For example, since most of thesecondary metal component may have already migrated to the surface offirst bonding element 212 subsequent to the bonding or the bonding plusannealing, the content of secondary metal component contained in thebulk of the first bonding element may be lower. When the first bondingelement 212 is a copper-titanium alloy in which the weight percentage ofsecondary metal component, titanium, may be about 5% or less by weight,the weight percentage of titanium in the self-forming diffusion linerlayer 230 may be, for example, at least greater than 95%.

Further, according to the exemplary embodiment of the disclosure, thebonding process may be a one-step bonding process or a two-stepbonding-plus-annealing process, depending on the types of metal alloyused in forming the bonding elements and/or other fabrication processrequirements.

The so-called one-step bonding process is applicable when the formationtemperature of the diffusion liner layer is substantially similar to thebonding temperature range. Accordingly, the bonding interface and thediffusion linear layer are concurrently formed during the bondingprocess.

In the one-step bonding process, the bonding interface and the diffusionliner layer 230 are formed concurrently because the diffusion linerformation temperature is within the range of the bonding temperature.The one-step bonding process may be performed at a temperature of about300° C. to 500° C. for at least 30 minutes, for example. Alternatively,the one-step bonding process may be performed at about 350° C. to about400° C. for about 30 minutes to 120 minutes.

The so-called two-step bonding-plus-annealing process is applicable whenthe formation temperature of the diffusion liner layer is higher thanthe bonding temperature range, in which a bonding interface is firstformed at the bonding temperature in the bonding process, and thediffusion liner layer is formed in the subsequent annealing process asthe temperature increases to the diffusion linear layer formationtemperature; accordingly, the bonding quality may also be improved.

In another exemplary embodiment of the disclosure, in the two-stepbonding-plus-annealing process, depending on the types of metal alloybeing applied, the bonding interface is formed at the bondingtemperature during a step of the two-step process, and the diffusionliner layer is formed at the diffusion liner formation temperature inanother step of the two-step process. Moreover, the two-stepbonding-plus-annealing process improves the bonding quality of thebonding structure. The first step of the two-step bonding-plus-annealingprocess may be conducted, for example, for about 30 minutes to about 60minutes, at a temperature between about 300° C. to 500° C. or betweenabout 350° C. to 400° C. The second step of the two-stepbonding-plus-annealing process may be conducted, for example, for about60 minutes to about 120 minutes, at a temperature between about 300° C.to 500° C. or between about 350° C. to 400° C. The first and the secondsteps of the two-step bonding-plus-annealing process may be performed ina same chamber or different chambers.

In accordance to an exemplary embodiment, prior to the bonding process,an adhesive film 250 may be applied on top surface 220 a of the secondsubstrate 220 surrounding the stud 222 a, as shown in FIG. 3A. In thisexemplary embodiment of the disclosure, the adhesive film 250 is formedon the lateral portion 222 b of the second bonding element 222 and thetop surface 220 a of the second substrate 220. Hence, subsequent to thebonding process, as shown in FIG. 3B, the gap between the firstsubstrate 210 and the second substrate 220 is filled with the adhesivefilm 250 to further enhance the bonding integrity of the bondingstructure.

Second Embodiment

FIGS. 4A to 4B are schematic cross-sectional views illustrating a methodof fabricating a bonding structure according to another exemplaryembodiment of the disclosure. Similar to the first exemplary embodiment,a first substrate 410 including at least a first bonding element 412,and a second substrate 420 includes at least a second bonding element422 are provided. In this exemplary embodiment of the disclosure, thefirst bonding element 412 is configured in a form of, for example, ametallized via created in the first substrate 410, while the secondbonding element 422 is configured in a form of for example, a T-shapedstructure with a stud 422 a protruding above the top surface 420 a ofthe second substrate 420 and a lateral portion 422 b embedded at the topsurface 420 a of the second substrate 420. A liner layer 418 may beformed between the non-bonding surfaces of the first bonding element 412and the first substrate 410. Additionally, a liner layer 428 may beformed between the second bonding element 422 and the second substrate420, between the stud 222 a and the lateral portion 222 b, and on someof the exposed non-bonding surface of the bonding element 422. Inaccordance to this exemplary embodiment of the disclosure, the lateralportion 422 b of the bonding element 422 is covered by the liner layer428, while all surfaces of the stud 422 a of the second bonding element422 are not covered by the diffusion liner layer 428. The material ofthe liner layer 218 includes, for example, tantalum (Ta), tantalumnitride (TaN), titanium (Ti), titanium nitride (TiN) or titaniumtungsten (TiW).

In this exemplary embodiment, the metallized via 412 is formed with ametal alloy having two or more metal components. Further, at least thestud 422 a of the second bonding element 422 is formed with a metalalloy having two or more components. In an exemplary embodiment of thedisclosure, the metal alloy used in forming the first metallized via 412and the stud 422 a is a copper-based alloy, for example. Thecopper-based alloy further includes a secondary component that includesone or more of titanium (Ti), magnesium (Mg), aluminum (Al) or chromium(Cr), for example. In this exemplary embodiment of the disclosure, theconcentration of the primary component (for example, copper) in themetal alloy may be for example, about 85% to 99.5% by weight, while theconcentration of the secondary component (for example, titanium) may be,for example about 15% to 0.5% by weight. The lateral portion 422 b ofthe second bonding element 422 may form with copper or theabove-mentioned copper alloy.

Continuing to FIG. 4B, the stud 422 a of the second bonding element 420is brought into alignment and in contact with the metallized via 412,and a bonding process is performed to connect the first substrate 410with the second substrate 420. The bonding process includes a thermalprocess, for example. The thermal process may be conducted at atemperature of about 300° C. to about 500° C. for at least 30 minutes.Alternatively, the thermal process may be conducted at a temperature ofabout 350° C. to about 400° C., and the duration of the thermal processmay range from about 30 minutes to about 2 hours. Depending on therequisite of the fabrication process, an annealing process may beperformed subsequent to the bonding process to enhance the bondingquality of the first bonding element 212 and the second bonding element222.

The bonding process may be a one-step bonding process or a two-stepbonding-plus-annealing process.

Still referring to FIG. 4B, during the bonding process, a diffusionliner layer 430 is formed at the exposed, non-bonded surfaces of thefirst bonding element 412 and the second bonding element 414. Morespecifically, the self-forming diffusion liner layer 430 is formed atthe exposed non-bonded surface 416 of the bonding surface of the firstbonding element 412 and at the exposed non-bonding surfaces 426 of thestud 422 a of the second bonding element 422. According to thisexemplary embodiment of the disclosure, the self-forming diffusion linerlayer 430 is generated mostly with the metal components of the metalalloy used in forming the first and the second bonding elements 412,422. For example, the self-forming diffusion liner layer 430 may beformed with the secondary metal component of the metal alloy (forexample, Ti in a Cu-Ti alloy) at the exposed, non-bonded surfaces 416,426 of the first bonding element 412 and the second bonding element 422.Alternatively speaking, the concentrations of the at least two metalcomponents in the diffusion liner layer 430, generated at the exposed,non-bonded surfaces of the bonding elements 412 and 422, may bedifferent from the concentrations of the at least two metal componentsin the bulk of the bonding elements 412 and 422. For example, afterbonding or bonding-plus-annealing, since the secondary metal componentmay have migrated to the non-bonded surfaces of the first bondingelement 412 and the second bonding element 422, the concentration of thesecondary metal component contained in the alloy in the bulk of thefirst bonding element 412 and the second bonding element 422 may belower. In an exemplary embodiment of the disclosure, when one metalcomponent (for example, the secondary metal component) of the alloy inthe bonding elements 412 and 422 may be, for example, about 5% or lessby weight, the one metal component (the secondary metal component) inthe self-forming diffusion liner layer 430 may be, for example, at leastgreater than 95%.

In accordance to the exemplary embodiment, an adhesive film 450 may beapplied on the top surface 420 a of the second substrate 420 prior tothe bonding process, as shown in FIG. 5A. According to this exemplaryembodiment of the disclosure, the adhesive film 450 is formed on thelateral portion 422 b of the second bonding element 422 and the topsurface 420 a of the first substrate 420, surrounding the stud 422 a.Hence, subsequent to the bonding process, as shown in FIG. 5B, the gapbetween the first substrate 410 and the second substrate 420 is filledwith the adhesive film 450 to better improve the bonding strength andintegrity of the bonding structure.

The bonding structure in the exemplary embodiments of the disclosure isdesigned to have a self-forming diffusion liner layer configured at theexposed, non-bonded surface of the bonding structure. The self-formingdiffusion liner is generated, during the formation of the bondinginterface, with the intrinsic components of the bonding elements used informing the bonding structure. Through the self-forming diffusion linerlayer provided by the disclosure, interaction between the metal, such ascopper, of the bonding structure and the ambient environment, such asair or adhesive, which may cause damages to the metal, can be prevented.Moreover, the problems of stress-induced voiding and electromigrationthat are often occurred in an exposed bonding structure are mitigated.Generally speaking, the bonding structure in the exemplary embodimentsof the disclosure is provided with good resistance to oxidation,electromigraion and stress-induced voiding, etc. Accordingly, thereliability of a bonding structure and the final device is improved.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of thedisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the disclosure covermodifications and variations of this disclosure provided they fallwithin the scope of the following claims and their equivalents.

1. A bonding structure, comprising: a first substrate comprising atleast a first bonding element; a second substrate disposed above oneside of the first substrate and comprising at least a second bondingelement, wherein the first bonding element is bonded to the secondbonding element, and at least one bonding element of the first bondingelement and the second bonding element is constructed with a materialcomprising an alloy including at least two metal components; a diffusionliner layer configured at an exposed, non-bonded surface of the at leastone bonding element, wherein the diffusion liner layer is constructedessentially with the at least two metal components from the at least onebonding element, and concentrations of the at least two metal componentsin the diffusion linear layer is different from the concentrations ofthe at least two metal components in the at least one bonding element.2. The bonding structure of claim 1, wherein a weight percentage of onemetal component of the at least two metal components in the at least onebonding element is between about 0.5% to about 15%, while the weightpercentage of the one metal component of the at least two metalcomponents in the diffusion liner layer is greater than 95%.
 3. Thebonding structure of claim 1, wherein the alloy is a copper-based alloy,which further comprises at least one of aluminum, titanium, magnesiumand chromium.
 4. The bonding structure of claim 3, wherein a weightpercentage of copper in the copper-based alloy is about 99.5% to about85%.
 5. The bonding structure of claim 1, wherein a liner layer isconfigured on some non-bonding surfaces of the first bonding elementand/or of the second bonding element.
 6. The bonding structure of claim1 further comprising an adhesive film between the first substrate andthe second substrate, and the adhesive film fills a gap between thefirst substrate and the second substrate.
 7. A bonding structure,comprising: a first substrate comprising at least a first bondingelement; a second substrate disposed opposite to one side of the firstsubstrate and comprising at least a second bonding element, wherein theat least first bonding element is bonded to the at least second bondingelement, and at least one bonding element of the at least first bondingelement and the at least second bonding element is constituted with amaterial comprising an alloy including at least a first metal componentand a second metal component, and a concentration of the first metalcomponent in the at least one bonding element is greater than aconcentration of the second metal component in the at least one bondingelement; and a diffusion liner layer configured at an exposed,non-bonded surface of the at least one bonding element, wherein thediffusion liner layer is constituted essentially of at least the firstmetal component and the second metal component obtained from the atleast one bonding element, and a concentration of the second metalcomponent in the diffusion liner layer is greater than the concentrationof the first metal component in the diffusion liner layer.
 8. Thebonding structure of claim 7, wherein first metal component is copper,and the second metal component comprises at least one of aluminum,titanium, magnesium and chromium.
 9. The bonding structure of claim 7,wherein a weight percentage of the second metal component in the atleast one bonding element is about 15% to about 0.5%, while the weightpercentage of the second metal component in the diffusion liner layer isat least greater than 95%.
 10. The bonding structure of claim 7, whereina weight percentage of the first metal component in the at least onebonding element is about 85% to about 99.5%.
 11. The bonding structureof claim 7, wherein a liner layer is configured at least between thefirst bonding element and the first substrate, and between the secondbonding element and the second substrate.
 12. A method of fabricating abonding structure, the method comprising: providing a first substratecomprising at least a first bonding element; providing a secondsubstrate comprising at least a second bonding element, wherein at leastone bonding element of the at least first bonding element and the atleast second bonding element is formed with an alloy comprising at leasttwo metal components; and performing a bonding process to fuse at leastthe first bonding element with at least the second bonding element andto form a diffusion liner layer at an exposed, non-bonded surface of theat least one bonding element.
 13. The method of claim 12, wherein thebonding process is performed at a temperature of about 300° C. to about500° C.
 14. The method of claim 12, wherein the bonding process isperformed for at least about 30 minutes.
 15. The method of claim 12,wherein the bonding process is performed at a temperature of about 350°C. to about 400° C.
 16. The method of claim 12, wherein the bondingprocess is performed for about 30 minutes to about 120 minutes.
 17. Themethod of claim 12, wherein the bonding process is a two-stepbonding-plus-annealing process.
 18. The method of claim 17, wherein afirst step of the two-step bonding-plus-annealing process is conductedat a temperature of about 300° C. to about 500° C. for about 30 minutesto about 60 minutes, and a second step of the two-stepbonding-plus-annealing process is conducted at temperature of about 300°C. to about 500° C. for about 60 minutes to 90 minutes.
 19. The methodof claim 12, wherein the diffusion liner layer is formed essentiallywith the at least two metal components from the at least one bondingelement.
 20. The method of claim 19, wherein concentrations of the atleast two metal components in the diffusion linear layer is differentfrom the concentrations of the at least two metal components in the atleast one bonding element.
 21. The method of claim 19, wherein a weightpercentage of one metal component of the at least two metal componentsin the at least one bonding element is between about 0.5 to about 15%,while the weight percentage of the one metal component of the at leasttwo metal components in the diffusion liner layer is greater than 95%.22. The method of claim 12, wherein the alloy is a copper-based alloythat further comprising at least one of aluminum, titanium, magnesiumand chromium.
 23. The method of claim 12, wherein an adhesive film isformed on at least a surface of the first substrate and the secondsubstrate, and the adhesive film fills a gap between the first substrateand the second substrate when the first bonding element is bonded to thesecond bonding element.
 24. The method of claim 12, wherein a linerlayer is formed on some non-bonding surfaces of the first bondingelement and/or of the second bonding element.
 25. A method offabricating a bonding structure, the method comprising: providing afirst substrate comprising at least a first bonding element on a surfacethereof; providing a second substrate comprising at least a secondbonding element on a surface thereof, wherein at least one bondingelement of the at least first bonding element and the at least secondbonding element is formed with an alloy comprising at least two metalcomponents; and performing a bonding process to bond the first bondingelement with the second bonding element and to generate a diffusionliner at an exposed, non-bonded surface of the at least one bondingelement, wherein the diffusion liner is generated with the at least twometal components from the at least one bonding element.
 26. The methodof claim 25, wherein a weight percentage of one metal component of theat least two metal components in the at least one bonding element isgreater than a concentration of another metal component of the at leasttwo metal components in the at least one bonding element, while theweight percentage of the one metal component of the at least two metalcomponents in the diffusion liner layer is less than the weightpercentage of the another metal component in the diffusion liner layer.27. The method of claim 25, wherein the alloy is a copper-based alloythat further comprising titanium.
 28. The method of claim 25, whereinthe bonding process is performed at a temperature of about 300° C. toabout 500° C. for about 30 minutes to about 120 minutes.
 29. A bondingstructure, comprising: a first substrate comprising at least a firstbonding element; and a second substrate comprising at least a secondbonding element and disposed opposite to one side of the firstsubstrate, and at least one bonding element of the at least firstbonding element and the at least second bonding element constructingwith an alloy comprising at least two metal components, wherein when thefirst bonding element is bonded to the second metal bonding element,weight percentages of the at least two metal components at an exposed,non-bonded surface of the at least one bonding element is different fromthe weight percentages of the at least two metal components at a bulk ofthe at least one bonding element.
 30. The bonding structure of claim 29,wherein the alloy is a copper-based alloy further comprising at leastone of aluminum, titanium, magnesium and chromium.